1. Field of the Invention
The present invention relates to a temperature sensor which is preferably used for measuring the temperature of a heating roller in a copier, a printer, or the like.
2. Description of the Related Art
In general, a temperature sensor for measuring the temperature of a heating roller used in a copier or a printer is placed in contact with the heating roller. As such a temperature sensor, for example, Patent Documents 1 and 2 disclose a temperature sensor that has a pair of lead frames, a thermal sensing element which is disposed between and connected to these lead frames, a holding portion formed at the ends of the pair of lead frames, and a thin film sheet which is provided at one side of the lead frames and the thermal sensing element to be brought into contact with the heating roller.
Such a temperature sensor is brought into contact with the surface of the heating roller using the elastic force of the lead frames so as to detect the temperature of the heating roller.
In Patent Document 1, a bead type thermistor or a chip thermistor is employed as the thermal sensing element. In Patent Document 2, a thin film thermistor in which a thermal sensing film is formed on one surface of an insulating substrate such as alumina is employed as the thermal sensing element. The thin film thermistor consists of a thermal sensing film formed on one surface of an insulating substrate, a pair of lead portions for connecting the thermal sensing film to a pair of lead frames, and a protective film for covering the thermal sensing film.
Patent Document 3 discloses a temperature sensor in which a thermocouple is integrated with a contact plate consisting of a metal. The temperature sensor brings the contact plate into contact with a measurement object by obtaining a contact pressure due to the elasticity of the contact plate to perform temperature measurement.